Genetic variation in Danaus plexippus L.: habitat selection or differences in activity times?

Spatial variation in Danaus plexippus (Lepidoptera: Nymphalidae) in south-east Queensland was studied using 2 gene loci, Pgm and Hbdh. Butterflies were sampled from 16 sites on each of two occasions, once in spring on a large spatial scale and again in late summer on a fine spatial scale. Levels of genetic variability, as measured by mean F statistics, were lower on both occasions than in a previous study. Significant spatial variation was detected on a fine scale at the Hbdh locus (F), and at both Pgm and Hbdh using spatial autocorrelation statistics. Differences in allele frequencies between sexes were again detected. There was no evidence for habitat selection. An alternative explanation for the spatial variation based on differences in activity times between genotypes is proposed